A framework for collateral risk control determination

This paper derives a general framework for collateral risk control determination in repurchase transactions or repos. The objective is to treat consistently heterogeneous collateral so that the collateral taker has a similar risk exposure whatever the collateral pledged. The framework measures the level of risk with the probability of incurring a loss higher than a pre-specified level given two well-known parameters used to manage the intrinsic risk of collateral: marking to market and haircuts. It allows for the analysis in a self-contained closed form of the way in which different relevant factors interact in the risk control of collateral (e.g. marking to market frequency, level of volatility of interest rates, time to capture and liquidity risk, probability of default of counterparty, etc.). The framework, which combines the recent theoretical literature on credit and interest risk, provides an alternative quantifiable and objective approach to the existing more ad-hoc rule-based methods used in hair cut determination. JEL Classification: E50, E58, G21, G10

Antibiofilm activity of LAE (ethyl lauroyl arginate) against food-borne fungi and its application in polystyrene surface coating

Several filamentous fungi species as Fusarium oxysporum or Cladosporium sp. can form biofilms by themselves or by participating in polymicrobial biofilms with bacteria. However, despite the high impact of biofilm on the food industry and the high efforts done to control biofilm produced by bacteria in the food area, there has been little study of strategies to control fungal biofilm in this area. In this study, the antibiofilm activity of the safe antimicrobial compound ethyl lauroyl arginate (LAE) was investigated against food spoilage fungi (Cladosporium cladosporioides, Aspergillus ochraceus, Penicillium italicum, Botrytis cynerea and Fusarium oxyspoum). Finally, the efficacy of a varnish-based coating incorporating LAE and coated onto polystyrene microtiter plates has been evaluated as a strategy to reduce fungal biofilm formation. The results of the 2,3-bis-(2-metoxi-4-nitro-5-sulfofenil)-2H-tetrazoilo-5-carboxanilida (XTT) assay, which measure the biofilm metabolic activity of moulds, demonstrated that LAE reduced significantly the formation of fungal biofilm at concentrations from 6 to 25 mg/L. This reduction was confirmed by the micrographs obtained by scanning electronic microscopy (SEM). In addition, LAE also showed antifungal activity against established biofilms. Particularly, it reduced their metabolic activity and viability at concentrations from 6 to 25 mg/L according to results obtained in the XTT assay and observations made by confocal laser scanning microscopy (CLSM). Finally, active coating incorporating from 2% of LAE proved to reduce significantly the biofilm formation in C. cladosporioides, B. cynerea and F. oxyspoum according to the results obtained in the XTT assay. However, the released studies indicated that the retention of LAE in the coating should be improved to prolong their activity

Les microsystèmes : technologies et traitement de l'information associé pour quelques applications

Les micro-systèmes représentent une nouvelle forme de systèmes possédant des qualités uniques en particulier de miniaturisation et de faible coût rendues possibles par les progrès des micro-technologies mises au point pour la réalisation de circuits intégrés. Dans cet article nous nous attachons à passer en revue les grandes familles de micro-capteurs et à mettre en évidence les traitements de l'information associés à chacun d'eux

Safety Assessment of Recycled Polyolefins for Food Contact Applications: Non-Target Screening of Volatile and Non-Volatile Substances

The thesis aims to establish sensitive and reliable sample pre-treatment methods as well as data analysis workflows to identify and quantify migrants from recycled polyolefins. Both volatile and non-volatile substances will be analysed in a non-target screening manne<br /

A collision cross section database for extractables and leachables from food contact materials

The chemicals in food contact materials (FCMs) can migrate into food and endanger human health. In this study, we developed a database of traveling wave collision cross section in nitrogen ((CCSN2)-C-TW) values for extractables and leachables from FCMs. The database contains a total of 1038 (CCSN2)-C-TW values from 675 standards including those commonly used additives and nonintentionally added substances in FCMs. The (CCSN2)-C-TW values in the database were compared to previously published values, and 85.7, 87.7, and 64.9% M + H](+), M + Na](+), and M - H](-) adducts showed deviations <2%, with the presence of protomers, post-ion mobility spectrometry dissociation of noncovalent clusters and inconsistent calibration are possible sources of CCS deviations. Our experimental (CCSN2)-C-TW values were also compared to CCS values from three prediction tools. Of the three, CCSondemand gave the most accurate predictions. The (CCSN2)-C-TW database developed will aid the identification and differentiation of chemicals from FCMs in targeted and untargeted analysis

New active antioxidant multilayer food packaging films containing Algerian Sage and Bay leaves extracts and their application for oxidative stability of fried potatoes

The antioxidant activity of Sage leaf (SL) and Bay leaf (BL) extracts was studied. Both plants were extracted using water and ethanol at different concentration, and the antioxidant activity was measured by ABTS [2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] radical cation scavenging and reducing power (RP) methods. In both cases 60% and 80% ethanolic extracts of Sage and Bay leaves showed the highest activity and were incorporated into multilayer films. The initial concentration for 60% ethanolic extracts of Sage and Bay leaves to scavenge 50% of free radical ABTS were 5.67 ± 0.26 µg × mL-1 and 18.68 ± 0.16 µg × mL-1 respectively, whereas for 80% ethanolic extracts the concentrations were 7.96 ± 0.02 and 14.65 ± 0.59 µg × mL-1 respectively. The initial concentrations of ethanolic 60% extracts of Sage and Bay leaves to allow absorbance 0.5 for reducing power were 35.38 ± 0.19 µg × mL-1 and 91.43 ± 2.84 µg × mL-1 respectively, while for 80% ethanolic extracts of Bay and Sage leaves were 46.01 ± 1.21 µg × mL-1 and 85.47 ± 0.9 µg × mL-1 respectively. Then, the multilayer films were exposed to a gas stream enriched with free radicals to evaluate the free radicals scavenging. The new packaging with 60% ethanolic Sage extract exhibited the highest activity with low percentage of hydroxylation (69.64 ± 6.86%) followed by that with 80% ethanolic extract for both Bay (85.49 ± 5.3%) and Sage (87.09 ± 3.93%) leaves extracts. The ability of two active packaging built with 60% ethanolic Sage extract and 80% ethanolic Bay extract to inhibit lipid oxidation of fried potatoes was studied by measuring secondary lipid oxidation products using thiobarituric acid reactive substances (TBARS). Significant lower value of Malondialdehyde (MDA) was obtained for fried potatoes stored in active packaging built with ethanolic 60% extract of Sage and 80% ethanolic extract of Bay leaves (0.342 ± 0.01 and 0.392 ± 0.02 µg MDA × g-1 respectively) at 40 °C for 20 days compared to the control (0.568 ± 0.03 µg MDA × g-1). Lipid oxidation decreased 40% and 31% for packaging with 60% Sage and 80% Bay ethanolic extracts respectively. The UPLC–MS–QTOF analysis of Sage and Bay leaves extracts revealed the presence of phenolic acids, tannins, flavonoids, and terpenoids. Migration tests from active materials demonstrated the absence of migration

Dynamic organization of ligand-grafted nanoparticles during adsorption and surface compression at fluid-fluid interfaces

Monolayers of ligand-grafted nanoparticles at fluid interfaces exhibit a complex response to deformation due to an interplay of particle rearrangements within the monolayer, and molecular rearrangements of the ligand brush on the surface of the particles. We use grazing-incidence small-angle X-ray scattering (GISAXS) combined with pendant drop tensiometry to probe in situ the dynamic organization of ligand-grafted nanoparticles upon adsorption at a fluid–fluid interface, and during monolayer compression. Through the simultaneous measurements of interparticle distance, obtained from GISAXS, and of surface pressure, obtained from pendant drop tensiometry, we link the interfacial stress to the monolayer microstructure. The results indicate that, during adsorption, the nanoparticles form rafts that grow while the interparticle distance remains constant. For small-amplitude, slow compression of the monolayer, the evolution of the interparticle distance bears a signature of ligand rearrangements leading to a local decrease in thickness of the ligand brush. For large-amplitude compression, the surface pressure is found to be strongly dependent on the rate of compression. Two-dimensional Brownian dynamics simulations show that the rate-dependent features are not due to jamming of the monolayer, and suggest that they may be due to out-of-plane reorganization of the particles (for instance expulsion or buckling). The corresponding GISAXS patterns are also consistent with out-of-plane reorganization of the nanoparticles

Prediction of collision cross section values: application to non-intentionally added substance identification in food contact materials

The synthetic chemicals in food contact materials can migrate into food and endanger human health. In this study, the traveling wave collision cross section in nitrogen values of more than 400 chemicals in food contact materials were experimentally derived by traveling wave ion mobility spectrometry. A support vector machine-based collision cross section (CCS) prediction model was developed based on CCS values of food contact chemicals and a series of molecular descriptors. More than 92% of protonated and 81% of sodiated adducts showed a relative deviation below 5%. Median relative errors for protonated and sodiated molecules were 1.50 and 1.82%, respectively. The model was then applied to the structural annotation of oligomers migrating from polyamide adhesives. The identification confidence of 11 oligomers was improved by the direct comparison of the experimental data with the predicted CCS values. Finally, the challenges and opportunities of current machine-learning models on CCS prediction were also discussed. © 2022 The Authors. Published by American Chemical Society

Prediction of Collision Cross-Section Values for Extractables and Leachables from Plastic Products

The use of ion mobility separation (IMS) in conjunction with high-resolution mass spectrometry has proved to be a reliable and useful technique for the characterization of small molecules from plastic products. Collision cross-section (CCS) values derived from IMS can be used as a structural descriptor to aid compound identification. One limitation of the application of IMS to the identification of chemicals from plastics is the lack of published empirical CCS values. As such, machine learning techniques can provide an alternative approach by generating predicted CCS values. Herein, experimental CCS values for over a thousand chemicals associated with plastics were collected from the literature and used to develop an accurate CCS prediction model for extractables and leachables from plastic products. The effect of different molecular descriptors and machine learning algorithms on the model performance were assessed. A support vector machine (SVM) model, based on Chemistry Development Kit (CDK) descriptors, provided the most accurate prediction with 93.3% of CCS values for M + H](+) adducts and 95.0% of CCS values for M + Na](+) adducts in testing sets predicted with <5% error. Median relative errors for the CCS values of the M + H](+) and M + Na](+) adducts were 1.42 and 1.76%, respectively. Subsequently, CCS values for the compounds in the Chemicals associated with Plastic Packaging Database and the Food Contact Chemicals Database were predicted using the SVM model developed herein. These values were integrated in our structural elucidation workflow and applied to the identification of plastic-related chemicals in river water. False positives were reduced, and the identification confidence level was improved by the incorporation of predicted CCS values in the suspect screening workflow

Polylactide-based films with the addition of poly(ethylene glycol) and extract of propolis—physico-chemical and storage properties

Polymeric films based on polylactide (PLA) with the addition of poly(ethylene glycol) (PEG) and a chloroformic extract of propolis were obtained. In the case of the studied films, polylactide (PLA) played the role of polymeric matrix and poly(ethylene glycol) was used as a plasticizer, while the extract of propolis was incorporated as a compound that could significantly affect the properties of the obtained materials, especially the water vapour permeation rate and the stability of the food products. Moreover, changes in structure, morphology, mechanical and storage properties as well as differences in colour, thickness and transparency after introducing propolis into the PLA–PEG system were determined. Based on the obtained results, it was established that the addition of the chloroformic extract of propolis significantly influences the most important properties taken into account during food packaging. It was also noticed that films with incorporated propolis were characterised by a significant improvement in the water vapour barrier property. Moreover, the obtained results prove that packaging containing a chloroformic propolis extract allow for the maintenance of the quality of the fruit stored for an extended period of time. To summarise, the application of a chloroformic propolis extract enables the formation of packaging materials that extend the shelf life of stored food products